Physically stable castor oil soluble victoria blue bo and a process of making it



Patented Aug. 15, 1950 MAKINGI'II' a Phillip ruerome-iwingate, Collins Park;

Ralphrflliiren.Ranckn CarneysToirimN J signers. tosEaLrdu. Pont da N'emours .85.

pany;,Wilmington;.Del., a corporation. 0t *Dela-Q wane N'iiinfawifigfi" Application October 21091 7 SeriahNo. 553 643.;

Thistsinvention'rrelates tosannimproved form of Victoria-PureBlue BOnvhiohha-s been defined in U. S. Patent No. 2,422,445 as a dyestufi which isgessentiallyswtlie hydrochloride: ofiijtetriaethyldiamino diphenyl ethyl alphas-amino r naphthyl-methanen. This-s improved form is soluble and stable in hot castor oil against crystallization.

Thersaid U. S. patent discloses in detail-:ithe

pneparationnof saidlcolor. andztea'ches a. specialt process.:forrlsolatingitin.aiorm which isisolublei: bathiinzwater andincastor hi1. The importance:

wherein represents the organic nucleus of the color, while the subscript ac is a number not less than 1.00 and not greater than 1.10. It has been observed however, that this color has a strong tendency to crystallize out of hot castor oil upon standing.

Such tendency is noxious to the copying paper maker, inasmuch as it is the custom to prepare a coating ink, by heating the various ingredients in castor oil to about 190-'210 F., and to keep the mixture hot for several hours while it is being gradually consumed in the coating of paper.

However, if the dye crystallizes out, the coating ink becomes viscous and grainy, and will not spread uniformly and smoothly over the paper.

It is accordingly an object of this invention to further modify the composition or form of Victoria Pure Blue BOO whereby to endow it with stability against crystal growth in hot castor oil, without impeding its other principal qualities, namely solubility in water and in castor oil. Other and further important objects of this invention will become apparent as the description proceeds.

Now, according to our invention, these objects are achieved by incorporating in the wet, precipitated dye, after the salting-out step and before drying, a small quantity (2 to 6% by weight based on the dry weight of color) of a polyhydroxy aliphaticzcompound; SllChffiS'. glycol, 'glycerineor-r pentaerythritohi andzthendrying the colon and .s grindingwitriin:the-ausualrmanner. We vfind that thdcfllbl'ihustreated possesses the same excellent solubility in: waterciandc in caster ,:'oilas';is. -;characteristic. ofal/ictoria Pure-Blue BGC, but: possesses-.- a the additional advantage of,":beingrstablezagainst crystahgrowth in. hot castor oil in: the temperature -rangesxofaits normal use:

It iswconceivable; that 'thisvnovelneftect is} due 1 toutheiormationof aloose compound between the dye and the polyhydroxy compound, say glycerina;

-insamanner si-milarto the formation of hydrates;

ofecrystalline substances: BUt' W'Q'dO not. desire;

to limitzthisrinventiona-to thisor: any otherrtheory y ofhactionz. Suiiice it; :to say :that: we have kept r solutions of our novel color in castor oil for as much as 24 hours, at temperatures between 180 and 220 F., and found the solution fluid and substantially free of crystals, whereas when our novel dye compound was replaced by ordinary Victoria Pure Blue BOC (that is one not treated with polyhydroxy compounds), crystallization after hour was sufficiently bad to make the mass viscous, gritty, and unsuitable for the production of carbon paper.

Without limiting our invention to any particular procedure, we ofier the following examples as illustrating our preferred mode of operation. Parts mentioned are by weight.

Example 1.

100 parts by weight of Victoria Pure Blue BOC (dry basis), obtained as a wet tar by salting the dye solution as described in Example 1 of U. S. 2,422,445, were mixed with 4 parts by weight of glycerine and the mixture was dried by heating in vacuo at C. until the resulting dye contained only 0.5 to 3% water.

For testing, 2 parts of the above dye were ground, mixed with 10 parts of castor oil and heated at 220 F. for 4 hours. No appreciable growth of color crystals was observed. The solution remained smooth and free flowing.

For comparison, a similar castor oil solution was prepared using Victoria Pure Blue 300 which had not been treated with glycerine. In this case, abundant growth of crystals was observed in the castor oil and the mixture became viscous and grainy.

Example 2.

The procedure of Example 1 was repeated except that the glycerine was replaced by an equal weight of pentaerythritol. The stabilized Example 3 The procedure of Example 1 was repeated in a series of experiments, except that the glycerine was replaced by an equal weight of glycol, diethylene glycol or sorbitol, respectively. In every case the dye so treated showed great resistance to'crystal growth in hot castor oil.

In a similar manner other polyhydroxy compounds were tested, including glyceryl-chlorhydrin and 2-methyl-2,4-pentanediol. All showed the same tendency to inhibit crystal growth.

We claim as our invention:

1. A process for improving the stability against crystal growth of the castor-oil-soluble grade of Victoria Pure Blue BO, which comprises incorporating into the wet, salted-out color, prior to drying, from 2% to 6% by weight (based on the weight of dry color) of an aliphatic'polyhydroxy compound selected from the group consisting of glycol, glycerine, pentaerythritol, diethylene glycol, sorbitol and 2-methyl-2,4- pentanediol, and then drying the color under a vacuum, whereby to retain the polyhydroxy compound in the color.

2. As a new composition of matter, a physically stable castor-oil-soluble form of Victoria Pure Blue BO whose molecules are intimately associated with an aliphatic polyhydroxy compound selected from the group consisting of glycol, glycerine, pentaerythritol, diethylene glycol, sorbitol and 2-methyl-2,4-pentanediol, the quantity of said polyhydroxy compound being from 2 to 6% by weight based on the dry weight of 4 the color, said composition being characterized by stability against crystal growth in hot castor oil.

3. A process for improving the stability against crystal growth of the castor-oil-soluble grade of Victoria Pure Blue BO, which comprises incorporating into the wet, salted-out color, prior to drying, about'4% by weight of glycerine (based on the weight of dry color) and then drying the treated press cake under vacuum, whereby to drive off substantially all of its water while retaining the glycerine.

4. As a new composition of matter, a physically stable castor oil soluble form of Victoria Pure Blue BO whose molecules are intimately associated with glycerine, the quantity of glycerine being from 2 to 6% by weight based on the dry weight of the color, said composition being characterized by stability against crystal growth in hot castor oil.

PHILLIP JEROME WINGATE. RALPH OLIVER RANCK.

The following references are of record in the file of this patent:

I REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,848,077 Huffman Mar. 1, 1932 2,086,745 Sell July 13, 1937 2,202,066 Platt May 28, 1940 2,208,551 Waters July 16, 1940 2,375,230 Kline May 8, 1945 2,361,505 Sheridan Oct. 31, 1944 2,435,905 Shaefer Feb. 10, 1948 

2. AS A NEW COMPOSITION OF MATTER, A PHYSICALLY STABLE CASTOR-OIL-SOLUBLE FORM OF VICTORIA PURE BLUE BO WHOSE MOLECULES ARE INTIMATELY ASSOCIATED WITH AN ALIPHATIC POLYDROXY COMPOUND SELECTED FROM THE GROUP CONSISTING OF GLYCOL, GLYCERINE, PENTAERYTHRITOL, DIETHYLENE GLYCOL, SORBITOL AND 2-METHYL-2,4-PENTANEDIOL, THE QUANTITY OF SLAID POLYHYDROXY COMPOUND BEING FROM 2 TO 6% BY WEIGHT BASED ON THE DRY WEIGHT OF THE COLOR, SAID COMPOSITION BEING CHARACTERIZED BY STABILITY AGAINST CRYSTAL GROWTH IN HOT CASTOR OIL. 